This invention relates generally to the rapid signature analysis characteristic of changes in an elastic membrane caused by stress, as a function of energy transmitted into the membrane and reflected therefrom. It relates particularly to a device for rapidly quantifying the relative distention of the bladder of a human subject as a function of ultrasonic energy transmitted into the subject and reflected therefrom.
There has been a long standing need for a device for rapidly quantifying the relative distention of bladders of human subjects, especially the mentally retarded, the infirm, and the elderly.
In attempts to normalize the lives of persons with mental retardation, much energy has been devoted to teaching these persons how to function independently in society. The problem of incontinence often thwarts the best of these efforts. While sophisticated toilet training programs are quite successful in teaching some persons what to do once the internal sensation of a full bladder is perceived, these programs typically presuppose that a person is capable of realizing when she/he has to void. The subset of the population of persons with mental retardation for whom continued incontinence is a more common problem are those persons with severe or profound mental retardation, i.e., those with IQs less than 35 and significant deficits in adaptive behavior, who have difficulty in recognizing the subtle and somewhat obscure signals of their bladders.
In addition, there is a substantial need to provide increased independence for persons who have permanently lost the ability to control their bladders for medical reasons such as diabetes, cerebral palsy, quadriplegia, spina bifida, and advanced age.
Incontinence typically results in a stigma for the person, reduced positive interaction with other people, unsanitary living conditions, excessive laundry expenses, and increased custodial attention by caregivers. Because of the failure to acquire fundamental toileting skills, such persons are often excluded from a wide variety of vocational, social, and recreational programs, in addition to many preschool programs--all of which are important components of overall experience necessary for their developmental growth and eventual integration into community life.
Previous attempts to employ technology in urinary toilet training fall into two classes. The first class is the wetness detector, which alerts the subject when urine is present on the person. A particular example of this is the employment of a moisture-sensitive apparatus in the clothing or in the bed, which device triggers an alarm when moisture is detected. The second class is the motion-sensitive device, which is located in the toilet. Once voiding has begun, the motion imparted to this device helps the user recognize that urination has been initiated. However, both classes of devices produce their effects after urination has taken place. That is to say, their users are helped to recognize when voiding has been initiated, but they are not helped to recognize the preliminary need to urinate, and thereby make the association between this need and socially-acceptable toileting behavior. In neither case is there a quantification of the relative distention of the bladder, which would be of significance in helping one to recognize the preliminary need to urinate.
Urologists have recently employed an ultrasonic device which scans the entire bladder and images it with a sector scan to show the extent of the bladder wall over a sixty degree angle. Other recently-developed devices are based on an ultrasonic "A" scan technique, using the time of flight of the sound wave between the front and back walls. These devices are typically bulky and expensive. Moreover, even the most sophisticated of the current devices suffers from inaccuracies resulting from the assumption of a simple, usually spherical, shape for the bladder. In actuality, the bladder is not a sphere, rectangle, or other simple geometric shape. It varies in shape continuously as it fills, varies in shape as between individuals, varies in height relative to the pelvic girdle as between the sexes, and if it ever did approach the point of becoming a sphere, hyperdistention would be imminent.
While 50 cc of urine is considered to be a significant void volume, void volumes in test subjects varied from 30 cc up to over 600 cc. The test population to date has tended to void between 180 and 400 cc. The subject perception is of increasing discomfort above approximately 200 cc. In individuals with urinary disfunction the bladder has been inflated through a catheter to upward of 600 cc with no real sensation being reported.
It is therefore a primary object of this invention to provide a device for the quantification of the relative distension of the urinary bladder of a human subject over a wide range of volumes, and with greater accuracy than any non-scanning ultrasound device available from the prior art.
A further object of this invention is to provide adaptability to the requirements of a human subject in a user selectable manner, thereby mimicking normal perception and affording help to the subject in recognizing the appropriate time to urinate. Since an intended application of the present invention is for individuals experiencing bladder disfunction for varying reasons and at varying ages, an adaptable operating system is a must. A microprocessor based design, with as much as possible of the functionality of the device in software, is indicated.
A further object of this invention is to provide a device for rapidly quantifying the relative distention of the bladder of a human subject, thereby providing vital information needed by the subject during the critical time when the bladder is at or near its full extention, and affording help to the subject in recognizing the preliminary need to urinate.
Other objects and advantages of this invention will become apparent in the specification and drawings which follow.